Jacking means for raising buildings of modular construction

ABSTRACT

A two-nut, short-stroke screw jack is disclosed having a central threaded member, upper and lower plates, a short-stroke hydraulic jack for lifting the load, and a novel arrangement for driving the upper and lower nuts. A single drive means is used to provide a continuous drive for the lower nut even when the lower nut does not rotate. The upper nut is driven by a resilient coupling means linking the upper and lower nuts. During the first portion of the lifting sub-step, the short stroke jack lifts the load while the drive means rotates the lower nut downwardly. During this first portion of the sub-step, the upper nut is wedged against the upper plate and does not rotate. The lower nut is driven downwardly until it is wedged against the lower plate and the drive means stalls out. During the second portion of the substep, the upper plate is lowered and the upper nut is driven downwardly by means of the resilient coupling linking the upper and lower nuts. The cycle is then repeated for the next stroke.

United States Patent [191 Csapo et al.

[451 Oct. 9, 1973 JACKING MEANS FOR RAISING BUILDINGS 0F MODULAR CONSTRUCTION [75] Inventors: Frank Csapo, Avon; Stanley J.

Filipek, Rush; Richard H. Horton, Pittsford; Richard A. Kull, North Chili, all of N.Y.

[73] Assignee: Stirling Homex Corporation, Avon,

[22] Filed: Feb. 24, 1972 [21] App]. No.: 228,934

Primary Examiner-Othell M. Simpson Att0rney--William D. Hall et a1.

[57] ABSTRACT A two-nut, short-stroke screw jack is disclosed having a central threaded member, upper and lower plates, a short-stroke hydraulic jack for lifting the load, and a novel arrangement for driving the upper and lower nuts. A single drive means is used to provide a continuous drive for the lower nut even when the lower nut does not rotate. The upper nut is driven by a resilient coupling means linking the upper and lower nuts. During the first portion of the lifting sub-step, the short stroke jack lifts the load while the drive means rotates the lower nut downwardly. During this first portion of the sub-step, the upper nut is wedged against the upper plate and does not rotate. The lower nut is driven downwardly until it is wedged against the lower plate and the drive means stalls out. During the second portion of the sub-step, the upper plate is lowered and the upper nut is driven downwardly by means of the resilient coupling linking the upper and lower nuts. The cycle is then repeated for the next stroke.

12 Claims, 21 Drawing Figures Patented Oct. 9, 1973 2 Sheets-Sheet 1 Patnted 0a. 9, 1973 2 Sheets-Sheet 2 IIH JACKING MEANS FOR RAISING BUILDINGS OF MODULAR CONSTRUCTION BACKGROUND OF THE INVENTION In U.S. Pat. No. 3,631,648, issued Jan. 4, 1972 for Method of Erection of High Rise Building Structures Formed of Modular Units; U.S. Pat. No. 3,726,053, issued Apr. 10, 1973, entitled Method and Apparatus for Erecting Modular High Rise Buildings; and U.S. Pat. No. 3,632,088, issued Jan. 4, 1972, entitled Means for Raising Building of Modular Construction; assigned to the assignee of this application; we have set forth some of the factors illustrating the necessity of evolving improved methods of building construction. These applications also present means and methods of constructing high rise buildings constructed of a plurality of small individual modules. The general building system envisions constructing the top floor of the building first from a plurality of the modules, and then raising the building with lifting jacks to one modular height. After the lifting operation has been completed, additional modules are secured in place in alternate bays of the building. The lifting jacks are then lowered and the building is thereby supported by the modules placed in the alternate bays. At that time, additional modules are set in place in the openings between the alternately spaced modules. After the entire floor has been completed, the top two stories 'are then raised and another row of alternate modules is then secured in place. The operation is repeated'until the building reaches its desired height.

In the aforesaid U.S. Pat. No. 3,632,088, a disclosure is made vof a combination supporting structure and jacking means which is capable of raising a module placed thereon and, as will be evident from the specification of the first U.S. Pat. No. 3,631,648, the jacking means has a lifting capacity of sufficient magnitude so as to be able to support and lift the weight of a number of modules rather than merely one. In fact, each jack means must lift the weight of at least twice as many modules as their are stories in the building. The present application is an improvement and alternate form of the jack means previously disclosed with reference to the combined supporting means and jacking means used in the erection of these high rise modular buildmgs.

SUMMARY OF THE INVENTION The present invention discloses a jacking means for raising one or more building modules by at least the height of a single story of the building. The jacking means comprises a short-stroke step jack having upper and lower nuts, and upper and lower plates with at least one short-stroke hydraulic jack placed between the upper and lower plates.

In the improved form of the invention, the upper and lower nuts are resiliently coupled together and a single drive means isused to rotateonly one of the lifting nuts, the other'nut being driven by means of a resilient coupling. During the first portion of a lifting sub-step, the short-stroke jack lifts the load while the drive means rotates the lower nut downwardly. During the first portion of the sub-step the upper nut remains wedged against the upper plate and does not rotate. The lower nut meanwhile is driven downwardly until it too is wedged against the lower plate and the drive means stalls out. During the second portion of the lifting sub-step, the hydraulic cylinders are retracted and the upper nut is then driven downwardly by means of the resilient connection or coupling linking the upper and lower nuts. The upper nut because it is resiliently connected to the lower nut will be advanced downwardly through the same degree of rotation as the lower nut was driven by the driving means. At this point, the lifting jack is ready to begin another sub-step. These sub-steps are repeated until the jack has raised the module to its desired height. I

It is another object of this invention to provide a failsafe support for the load being carried and raised in the event that any failure in the hydraulic system occurs. Since the jack is a short-stroke step jack, the centrally threaded jack post and the upper and lower nuts provide a follow-up system which is available to support the load in the event that there is a failure of any of the hydraulic driving means. Additionally, means are provided for limiting the movement of the hydraulic drive in either direction to provide further protection against system failure.

It is another object of this invention to provide a short-stroke hydraulic step jack for use in the construction of buildings which minimizes the number of hydraulic motors and jacks required to raise the modular component. It is an object of this invention to disclose a novel resilient coupling for the two nuts that eliminates the necessity for a secondary drive means for the upper nut.

It is another object of this invention to provide a short stroke hydraulic step jack for use in raising an extraordinarily large loadthat will not require an excessive amount of hydraulic fluid for actuation. Since the normal load carried by one of these jacks runs between and tons, and since the length of the stroke required to lift a module to full height is one the order of ten feet, the amount of hydraulic fluid needed becomes extraordinarily large. By substituting a short-stroke jack for the single stroke jack, one is able to greatly reduce the amount of fluid required, and improve the jacking tolerance. Since the modules and the building are raised by a plurality of jacks, it is important that the jacking level of each of the jacks be maintained within a rather strict tolerance. The short-stroke stepping jack enables a more precise control of the variations between the respective jacks used to raise the building.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a cross-sectional view of the jacking mechanism of the present invention.

FIG. 2 is an isometric and representational view of the resilient coupling linking the upper and lower nuts.

FIG. 3 is an isometric and representational view of an alternate embodiment of the upper and lower nuts of the present invention.

FIG. 4 is a cross-sectional and diagrammatic view of the jacking means according to the present invention before beginning a sub-step of operation.

FIG. 4A is a diagrammatic view of the relative location of the upper and lower nuts before beginning a sub-step of operation.

FIG. 5 is a cross-sectional and diagrammatical view of the jacking means according to the present invention during the first portion of the upward mode of operation.

FIG. 5A is a diagrammatical view of the relative location of the upper and lower nuts during the first portion of the upward mode of operation.

FIG. 6 is a cross-sectional and diagrammatical view of the jacking means according to the present invention during the first portion of the upward mode of operation and illustrates a change of state in the jacking device during the first portion of the sub-step.

FIG. 6A is a diagrammatical view of the relative location of the upper and lower nuts during the first portion of the upward mode of operation and illustrates a change of state that occurs at the completion of the first portion of the sub-step.

FIG. 7 is a cross-sectional and diagrammatical view of the jacking means according to the present invention during the second portion of the upward mode of operation.

FIG. 7A is a diagrammatical view of the relative location of the upper and lower nuts during the second por tion of the upward mode of operation.

FIG. 8 is a cross-sectional and diagrammatical view of the jacking means according to the present invention during the second portion of the upward mode of operation and illustrates a change of state in the jacking device during the first portion of the sub-step.

FIG. 8A is a diagrammatical view of the relative location of the upper and lower nuts during the second portion of the upward mode of operations and illustrates a change of state that occurs at the completion of the first portion of the sub-step.

FIG. 9 is a cross-sectional and diagrammatical view of the jacking means according to the present invention during the first portion of the downward mode of operation.

FIG. 9A is a digrammatical view of the relative location of the upper and lower nuts during the first portion of the downward mode of operation.

FIG. 10 is a cross-sectional and diagrammatical view of the jacking means according to the present invention during the second portion of the downward mode of operation and illustrates a change ofstate in the jacking device during the first portion of the sub-step.

FIG. 10A is a diagrammatical view of the relative location of the upper and lower nuts during the second portion of the downward mode of operation and illustrates a change of state that occurs at the completion of the first portion of the sub-step.

FIG. 11 is a cross-sectional and diagrammatical view of the jacking means according to the present invention during the second portion of the downward mode of operation.

FIG. 11A is a diagrammatical view of the relative location of the upper and lower nuts during the second portion of the downward mode of operation.

FIG. 12 is a cross-sectional and diagrammatical view of the jacking means according to the present invention during the second portion of the downward mode of operation and illustrates a change of state in the jacking device during the first portion of the sub-step.

FIG. 12A is a diagrammatical view of the relative location of the upper and lower nuts during the second portion of the downward mode of operation and illustrates a change of state that occurs at the completion of the first portion of the sub-step.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The lifting device of the present invention includes a short-stroke step-jack and first and second nuts threadably engaged on a helically threaded lifting or jack post. These nuts are engaged by upper and lower plates, which are in turn activated by short-stroke hydraulic cylinders. The central jack post carries at its upper end means for engaging the load to be lifted, and extends downwardly into a support base. The lower plate comprises the upper portion of the support base which extends downwardly to the ground or the structure supporting the jack and the load to be lifted.

During the first portion of the upward mode of operation, the short-stroke hydraulic cylinders elevate the upper plate, which in turn elevates the upper nut, thereby raising the central jack post and the load to be lifted. The load is transmitted through the post via the upper nut to the upper plate and thence to the hydraulic cylinders, and from the cylinders to the lower plate and support means. As the load is elevated, the lower nut is advanced downwardly until it engages the lower plate, and motor 50 stalls out. The hydraulic cylinders and upper plate are retracted for the second portion of the upward mode of operation. The load is now shifted from the upper nut to the lower nut which in turn transmits the load to the lower plate and support means. The upper nut is then advanced downwardly to correspond with the advancement of the lower nut.

In the present invention, where a building of 15 to. 20 stories is elevated, the total vertical load will run between 2 and 3 hundred thousand pounds for each jack. The horizontal wind loading with a 50 mile an hour wind will present a horizontal load on the jacks of 10 to 20 thousand pounds. These jacks must not only lift a substantial load, they must also be able to lift the load through a substantial distance. They must also be able to lift the load through this long stroke with a substantial sideward force exerted thereon. Since each of the modules is approximately 10 feet in height, the normal stroke of each jack will be one full module height or 10 feet.

A jack constructed in accordance with the present invention will have a central post or jack screw approximately 12 and a half inches in diameter, and upper and lower nuts approximately 16 inches in diameter. By using relatively small short-stroke lifting cylinders, the working pressure for the hydraulic system may be limited to approximately 2000 psi.

Each sub-step of operation will elevate the load approximately one sixteenth of an inch. With this substep, the jack will elevate the load approximately one half inch to 1 inch per minute of operation. This means that the entire building can be elevated the required 10 feet in 2 to 4 hours. Provision is also made for fastjacking or fast return wherein the jack may be returned approximately 2 inches per minute or approximately one hour for the ten foot jacking stroke.

FIG. 1 is a cross-sectional view of a jack constructed in accordance with the present invention. It illustrates the support base 1 l, upwardly extending support member 12 and a threaded jack post 13. The jack post carries a jack head 14 for engaging a load to be lifted. The load to be lifted is carried by the central jack post 13 which extends through the full length of the recipro' cal motion of said jack. At the beginning of operation,

jack head 14 is adjacent the upper nut 16 while the lower portion of the central jack post 14A is carried within the upright support member 12.

The threaded post 13 has mounted thereon first and second nuts and 16. Nut 15 engages the threads of central post 13, and rests upon the lower plate 17 when the jack-is at rest. The upper and lower nuts 15 and 16 are connected together by means of the resilient connection 18 which will be hereinafter described. The upper nut 16 is suspended slightly above the upper plate 19. Nut 16 extends downwardly through an opening 20 in the upper plate 19 to drive plate 21 by means of a collar 22. Thus as illustrated in FIG. 1, the upper nut comprises the threaded nut portion 16, collar 22, and-drive plate 21.

The hydraulic lifting means for the jacking device comprises two short-stroke two-way hydraulic culinders and 31 mounted on the lower plate 17. The cylinder rods 32 and 33 of these hydraulic cylinders 30 and 31 extend upwardly to the upper plate 19 which is located between the lower and upper nuts 15 and 16. Cylinder rods 32 and 33 are securely fastened to the upper plate 19 by means of bushings 34 and 35 and nuts 36 and 37. The bushings 34 and 35 are provided with a relatively loose fit in plate 19 so as to eliminate the need for precise alignment of the respective apertures in plate 19 relative to the central opening 20.

The downward movement of upper plate 19 is limited by means of collars 38 and 39 which surround the tie rods 40 and 41. Upper plate 19 is also limited in its upward travel by means of tie rods 40 and 41. The actual sub-step of each stroke of the hydraulic cylinders 30 and 31 is limited to upward and downward strokes on the order of three-sixteenths of an inch with a net upward or downward movement of jack post 13 of onesixteenth of an inch. The collars 38 and 39 and tie rods 40 and 41 assist in the protection of the device in the event of a component failure. Additionally, the collars will protect the cylinders and support the load in the event the upper or lower nuts fail to advance during a sub-step of operation.

The lower nut 15 is driven by means of a hydraulic motor 50 which rotates shaft 51 and spur gear 52. The upper nut 16 is indirectly driven by means of motor 50 through the resilient coupling 18 and drive plate 21 which will be hereinafter'later described.

The resilient interconnection between the upper and lower nuts is illustrated in FIG. 2. The upper threaded portion 16 is not illustrated. Only the drive plate 21, collar 22, and the lower nut 15v are illustrated in FIG. 2. The drive plate 21 defines a pair of arcuate slots 60 and 61. The lower nut 15 defines a single arcuate slot 62 which extends over a slightly greater arcuate distance than the slots 60 and 61. The outer arcuate limits of slots 60 and 61 are so constructed as to coincide with the normal or at rest location of pins 63 and 64. These pins 63 and 64 are affixed to slide means 65 and 66 which slide in slot 62. These slides are biased to the outer extremities of slot 62 by means of coil spring 67.

In normal operation, the drive plate 21 is fitted over lower nut 15 with the upwardly extending pins 63 and 64 extending through slots 60 and 61. These pins 63 and 64 contact the outer extremities 60A and 61A of slots 60 and 61.

Drive plate 21 is suspended above nut 15 by a distance of one-sixteenth to one-eighth of an inch. This distance varies depending on the phase or portion of the sub-step completed. The slots 60 and 61 allow the pins 63 and 64 to reciprocate vertically while maintaining a driving or driven relationship with drive plate 21.

During the first portion of an upward sub-step, the drive plate 21 and nut 15 are maintained in rotational coincidence as determined by spring 67 which upper nut 16 is restrained from rotating by virtue of its frictional engagement with the upper plate 19. Therefore plate 21 is not allowed to rotate. The lower nut 15 on the other hand is rotated by motor 50 through a given angle of rotation dependent on the amount by which the screw 13 and lower nut were raised by cylinders 30 and 31. Nut 15 is driven into engagement with plate 17, and the hydraulic motor 50 is stalled out. This angle of rotation is clockwise in motion and results in a storing of energy in spring 67 as pin 64 abuts the end 60A of slot 60. The pin 64 remains stationary, but its relative movement with respect to nut 15 is counter-clockwise.

During the secondportion of the upward sub-step the upper plate 19 is lowered by the hydraulic cylinders 30 and 31. This releases the upper nut 16 for rotational movement. The resilient spring 67 will then release its stored energy and drive pin 64 in a clockwise movement which results in a clockwise rotation of drive plate 21. This in turn rotates upper nut 16 and causes it to advance downwardly through the same angle of travel as did lower nut 15.

The second slot 61 and the pin 63 are used when the jack is lowering, a load, and the operation is reversed insofar as the rotational movement is concerned. When the jack is being lowered, the lower nut is driven in a counter-clockwise motion. Pin 63 remains stationary, but its relative movement with respect to nut 15 is clockwise during the first portion of the downward substep, and a counter-clockwise movement during the second portion of the sub-step. Pin 63 engages the end of the slot 61 indicated by the numeral 61A.

FIG. 3 represents an alternate embodiment of the resilient-connection interconnecting the upper and lower nuts. Again, only the drive plate 21 is illustrated and when assembled, the lower nut 15 and drive plate 21 are placed immediately adjacent one another. The

plate 21 has extending downwardly a fixed pin 70 within arcuate slots 73 and 74 and are urged into engagement with pin by means of springs 75 and 76. These springs are secured against further movement by the ends 73A and 74A of slots 73 and 74.

In the embodiment illustrated in FIG. 3, the drive plate 21 is held in place during the first cycle of operation by virtue of the frictional engagement between the upper nut 16 and upper plate 19. As the jacking assembly is lifted by means of cylinders 30 and 31, the lower nut 15 is driven downwardly in a clockwise direction which again results in a counterclockwise compression of spring 76 within slot 74. After the lower nut 15 has been driven into frictional engagement with the lower plate 17, the cylinders 30 and 31 are released, and the upper plate 19 is allowed to descend. As plate 19 descends, it no longer frictionally engages the upper nut 16, and nut 16 is allowed to rotate in a clockwise manner by virtue of the resilient bias exerted upon pin 70 and drive plate 21 by spring 76. Conversely, when the jack is being lowered, the opposite is true, and spring 75 is compressed by means of a counter-clockwise movement of nut 15.

Referring to FIGS. 4-12, FIGS. 4 and 4A are diagrammatical views of a jack constructed in accordance with the present invention during its at rest or normal position. FIGS. 5 through 8 illustrate the upward mode of operation while FIGS. 9 through 12 illustrate the downward mode of operation.

Referring specifically to FIG. 4, the upper nut 16 is illustrated as being one-eighth inch above the upper plate 19. The lower nut abuts the lower plate 17. The load at this point is being carried by central jack screw or post 13 to the lower nut 15 and through nut 15 to plate 17. It in turn is supported by the jack support structure as previously described with respect to FIG. 1.

FIG. 4A illustrates the relative locations of the upper and lower nuts while the jack is at rest. Upper nut 16 is signified by the outer circle and the lower nut 15 is signified by the inner circle. Points 15A and 16A provide relative reference points that illustrate and correspond to the actual rotation of nuts 15 and 16 in relation to an external fixed point such as the jack support base. 158 illustrates the sliding connection of pin 64 within the slot 62 defined in the lower nut 15. Point 168 defines the point connection of pin 64 as it abuts the end 60A of slot 60.

FIG. 5 is a cross-sectional and diagrammatic view of the jacking means according to the present invention during the first portion of the upward mode of operation. As illustrated in FIG. 5, the upper plate 19 has been elevated by means of the short-stroke hydraulic cylinders and 31. They have engaged the upper nut 16 and have transferred the load from the bottom nut 15 to the top nut 16. The load is now being carried through the jack post 13 and upper nut 16, to plate 19, and from plate 19 downwardly through the hydraulic cylinders 30 and 31 to the support base or lower plate 17 and the support means for the jack. During the upward motion of the jack cylinders 30 and 31, the upper plate 19 frictionally engages the upper nut 16 and prevents its rotation. During this portion of the sub-step, the load is lifted from the bottom nut, and the drive means 50 is then allowed to drive the lower nut 15 downwardly against the bottom plate 17 as indicated in FIG. 6.

The completion of the first portion of the substep is illustrated in FIGS. 6 and 6A. Simultaneously with the elevation of plate 19, the bottom nut 15 is frictionally engaged with the lower plate or support means 17 and the hydraulic motor 50 is stalled. As illustrated in FIG. 6A, both points 158 and 168 have moved through an angle of approximately 34 from the position they occupied at the beginning of the cycle. As indicated by points 15A and 16A, their relative angular rotation of the upper and lower nuts are different by the corre sponding angle of rotation. That is, the lower nut has rotated clockwise through an angle of 34 while the upper nut has remained essentially stationary.

FIGS. 7 and 7A are cross-sectional and disgrammatical views of the jacking means according to the present invention during the second portion of an upward substep. As indicated, the lower nut 15 is now wedged tightly against the lower plate or support means 17, and the hydraulic cylinders 30 and 31 are retracted, thereby lowering the upper plate 19 and releasing the upper nut 16 from its frictional engagementtherewith.

8 Once upper nut 16 is free to rotate, it is driven downwardly as illustrated in FIGS. 8 and 8A by spring 67 and drive plate 21. During this period of rotation, it ad vances downwardly and rotates angularly through the angle of rotation previously accomplished by the lower nut 15. The angle of rotation for the upper nut 16 is also 34, and at the end of the second portion of the sub-step, the reference points 15A and 16A again coincide but both have moved through an angle of 34 from the beginning of the sub-step. At this point, the spring 67 is no longer under compression, and pin 64 has resumed its normal position in slot 62. During the second portion of an upward sub-step, the load is transferred from the upper nut 16 to the lower nut 15 and from lower nut 15 to the lower plate or support means 17.

The following chart illustrates the relative movements between the lower nut 15, the lower plate 17, the upper nut 16, the upper plate 19, the rotation of the bottom nut, the rotation of the top nut, the amount of lift of the hydraulic cylinders 30 and 31, and the movement between the bottom of plate 21 and the top of the lower nut 15. These relationships are set forth for FIGS. 4, 5, 5A, 6, 6A, 7, 7A, 8 and 8A.

30 Figs. 5 Figs. 6 Figs. 7 Figs. 8 Fig. 4 and 5A and 6A and 7A and 8A A Bottom of lower nut 15 to 0 Mo 0 0 0 top of lower plate 17, in.

B. Bottom of upper nut 16 to 0 0 ia }s top of upper plate 19, in. Bottom nut rotation CW 0 0 34 0 0 (15), deg. Top nut rotation CW (16), 0 0 O 0 34 deg. Screw lift (13), in 0 ){e No further raising C Bottom of drive plate 21 to ){a lie is is lie top of lower nut 15, in. Cylinder movement (30 0 1 M6 0 2 ie 0 and 31), in.

1 Up. 2 Down.

steps or at rest. FIGS. 9 and 9A are cross-sectional and diagrammatic views of the jacking means according to the present invention during the first portion of a downward sub-step.

During a downward sub-step, the rotational movement of motor 50 is reversed to cause the lower nut 15 to be driven in a counter-clockwise direction rather than a clockwise direction. The nut 15 is driven upwardly along shaft 13 rather than downwardly as in the case of an upward sub-step. During the first portion of the downward sub-step illustrated in FIG. 9 and 9A, the lift cylinders 30 and 31 raise the upper plate 19 and engage the upper nut 16 to prevent any rotation of nut 16.

As nut 16 is wedged against upper plate 19, and as the load is transferred from lower nut 15 to upper nut 16, the lower nut 15 becomes free to rotate, and is rotated by hydraulic motor 50 in a counter-clockwise direction or upward along shaft 13 a distance of onesixteenth of an inch. As will be noted in FIG. 10A, this rotation in a counter-clockwise motion is approximately 34 for a sixteenth of an inch change in the position of lower nut 15.

The downward mode of operation is different from I the upper mode of operation in that, to lower the load,

it first must be raised one-sixteenth of an inch, and then lowered one-eighth of an inch. The second portion of the downward sub-step wherein the load is lowered one-eighth of an inch, is illustrated in FIG. 11 and 12.

As noted in FIG. 10A, the lower nut has been advanced in a counter-clockwise motion approximately 34, while the upper nut has remained stationary. At this point in the sub-step, the resilient spring 67 is exerting a substantial counter-clockwise force on the upper nut 16.

As illustrated in FIG. 11, during the second portion of a downward sub-step the upper plate 19 is lowered, thereby releasing the pressure and friction on upper nut 16. This allows it to rotate downwardly as illustrated in FIG. 12A. The net movement of shaft 13 is onesixteenth of an inch downward. After the load has been transferred to nut 15, the upper plate 17 is lowered by the hydraulic cylinders 30 and 31. Upper nut 16 is then driven upwardly to the same degree that the lower nut 15 was advanced upwardly. As illustrated in FIG. 12A, at the completion of the second portion of the downward sub-step, the spring means 67 has driven the upper nut upwardly to equalize the tension in the coupling assembly.

The following chart sets forth the dimensions and movements during the downward sub-step in a manner similar to the chart above which set forth the motions and movements for the upward mode of operation. Again, it is intended to be representational only, and sets forth the characteristics of one embodiment ofthe invention. It is to be understood that these dimensions and degrees of rotation will vary depending upon the size of the load to be lifted, and the other design parameters that enter into the physical construction of the jack.

Figs. 4 Figs. 9 Figs. 10 Figs. 11 Figs. 12 and 4A and 9A and 10A and 11A and 12A A-.. Bottom of lower nut 15 0 s 0 0 to top of plate 17, in.

B... Bottom of upper nut 16 ls 0 0 Ha ,s

to top of plate 19, in. Lower nut rotation 0 0 34 0 0 CCW deg. Upper nut rotation 0 0 0 0 34 CCW (16), deg. Screw axial movement 0 lie 0 Hz 0 C.. Bottom of drive plate M0 is 0 0 Ma 21 to top of lower nut 15, in. Cylinder movement 0 1 5h; 0 2 its 0 and 31 in.

1 Up. 2 Down.

As was pointed out previously, there is provided for the present jacking means a method of operation which will enable the jack to be moved in a fast jacking mode of operation. In this mode of operation, the relative movement of the central jack post 13 is approximately twice as fast as it would normally be. It is therefore possible to lower the jack its entire length in approximately 1 hour. The relative rate of movement is approximately 2 inches per minute.

As has been pointed out during the discussion of the jack during its normal cycle of operation, motor 50 runs continuously, and is stalled out during alternate cycles of the jacks operation. It is stalled because of the relatively enormous load that is placed upon the lower nut 15, and the friction that is thereby engendered between lower nut 15, and the lower block or support base 17. Motor 50, however, is strong enough to rotate the lower nut when no load is placed upon the jack, so that the hydraulic motor will drive the bottom nut in a counter-clockwise direction continuously when the jack is in its fast jacking mode of operation. Due to the resilient connection between the upper and lower nuts exerted by spring 67, the upper nut will follow in a rotational movement lower nut 15, and the shaft 13 will be advanced downwardly into the columnar support base 12 by the relative rotation of the upper and lower nuts 15 and 16.

Conversely, the hydraulic motor 50 is also strong enough to lift the central jack post 13 when there is no load to be carried by jack head 14. The direction of the motor is reversed, and the lower nut is driven in a clockwise direction thereby elevating the jack post 13 out of the columnar support area 12. Again the upper nut follows the rotation of lower nut 15 by means of the resilient connection therebetween.

While it is apparent the jacking system of the present invention could be controlled manually by an operator 7 starting and stopping the flow of hydraulic fluid to cylinders 30 and 31, it is intended that a plurality of these jacks be used together to raise an entire building.

-A control system is normally provided to coordinate a plurality of these jacks to insure the elevation of the load is evenly distributed between the jacks. The control system senses the movement of the upper plate 19 and after the cylinders have moved plate 19 through a predetermined distance, the supply of hydraulic fluid is interrupted. After nut 15 has completed its downward rotation, the two-way hydraulic cylinders are retracted and nut 16 is driven downwardly by the coupling means.

While the present invention has been illustrated with the hydraulic drive means 50 as a drive means for the lower nut, it is to be understood that the arrangement of plates and nuts could be reversed with the drive means 50 driving the upper nut. It would also be possil e elestxiqmqw for the ve ea While the present invention has been illustrated with compression springs, it would be possible to rearrange the springs and provide for a tension spring drive rather than a compression spring drive. It would also be possible to replace collar 22 with a torsional spring member to provide a resilient drive for the other nut.

While the present system uses short-stroke hydraulic lift cylinders 30 and 31, any type of short-stroke lifting device could be used, including short-stroke lifting wedges, wherein the wedges are driven laterally to provide an upward lift.

It is to be understood that, although one specific arrangement of lifting means, nuts and plates has been used, the present invention is applicable to any twonut, short-stroke jacking system wherein the jack load is elevated by means ofa short-stroke lifting means and the load is then carried by one of the nuts while the lifting means prepares for another stroke. Although two embodiments of the resilient connection between the upper and lower nuts have been shown in the drawings and described in considerable particularity in the foregoing specification, it is to be understood the invention is not limited to the specific details and forms shown and described, but includes all modifications coming within the scope of the appended claims and their equivalents.

We claim:

1. Jacking apparatus of the type which includes a jacking element for raising a load through a plurality of successive sub-steps and comprising:

a. support means,

b. a threaded screw,

c. means coupling said screw to the load,

d. a first nut threadably engaging said screw and at times supported by said support means,

e. a second nut also threadably engaging said screw,

f. load lifting means for at times moving said second nut together with said screw and the load in the direction of the screw axis,

g. nut rotating means for rotating only one of said nuts selectively in either direction about said screw,

h. coupling means operatively connected between said first and second nuts and tending to maintain said two nuts in rotatably coincident positions on said screw,

i. whereby the action of said lifting means in urging said load away from said support means tends to move said first nut away from said support means and frees said first nut for rotation while simultaneously causing the load to be carried by said screw and through said second nut to said lifting means,

and whereby the relieving of said lifting means causes the load to be carried instead through said first nut to said support means while simultaneously freeing said second nut for rotation,

j. and means for restraining rotation of said one nut except in response to said nut rotating means and of the other nut except in response to said coupling means.

2. Jacking apparatus as claimed in claim 1 wherein said coupling means comprises a resilient means.

3. Jacking apparatus as claimed in claim 2 wherein said resilient means comprises a spring and means responsive to rotation of said one nut by said nut rotating means for storing energy in said spring.

4. Jacking apparatus as claimed in claim 3 wherein said spring is a compression spring mounted on either of the two nuts and said coupling means further includes means responsive to rotation of either nut from a predetermined position of rotational coincidence of the two nuts for compressing said spring.

5. The jacking apparatus of claim 4 which further includes an arcuate slot in said one nut for housing said spring, at least one upstanding pin slidably supported in said slot at an end of said spring, and an aperture in said other nut for securing said pin.

6. The jacking apparatus of claim 5 in which there are two upstanding pins slidably supported in said slot at opposite ends of said spring, said other nut defining therein two spaced arcuate slots each respectively securing one of said pins, the remote ends of said two spaced slots being spaced circumferentially by a distance corresponding to the circumferential spacing of said two pins when said two nuts are in said rotationally coincident position, the length of each of the spaced arcuate slots being such as to subtend an angle at least equalling the angular rotation imparted to said one nut by said nut rotating means.

7. Ajacking apparatus as claimed in claim 1 wherein said support means restrains the rotation of said first nut when the load is supported by said support means through said first nut.

8. A jacking apparatus of the type having a support means, a threaded screw, a means coupling the screw to the load, a first nut threadably engaging said screw and at times supported by said support means, a second nut also threadably engaging said screw, and load lifting means for at times moving said second nut together with said screw and the load in the direction of the screw axis, the improvement which comprises: a drive means for rotating only one of said nuts selectively in either direction about said screw, a coupling means which is operatively connected between said first and second nuts and which tends to maintain said nuts in rotatably coincident positions on said screw, and means for restraining the rotation of said one nut except in response to said drive means and the rotation of said other nut means except in response to said coupling means,

whereby the action of said lifting means in urging said load away from said support means tends to move said first nut away from said support means and frees said first nut for rotation while simultaneously causing the load to be carried by said screw and through said second nut to said lifting means; and whereby the release of said lifting means causes the load to be carried instead through said first nut to said support means while simultaneously freeing said second nut for rotation.

9. A jacking apparatus as claimed in claim 8 wherein said coupling means comprises a resilient means.

10. Jacking apparatus of the type which includes a jacking element for raising the load through a plurality of successive sub-steps and comprising:

a. a base having an upwardly extending support means,

b. a helically threaded jack post,

0. means coupling said jack post to the load,

d. a first lower nut threadably engaging said jack post and at times supported by said support means, said support means restraining rotation of said lower nut when supporting said nut,

e. a second upper nut also threadably engaging said jack post,

f. short-step load lifting means for at times moving said upper nut together with said jack post and the load in the direction of the post axis, said load lifting means restraining the rotation of said upper nut when said jack post is moved by said lifting means,

g. drive means for rotating only one of said nuts selectively in either direction along said jack post,

the load to be carried instead through said lower nut to said support means while simultaneously freeing said second nut for rotation. 11. A jacking apparatus as claimed in claim 10 which further comprises a lifting plate mounted between said upper and lower nuts with said load lifting means being mounted between said support means and said lifting means.

12. A jacking apparatus as claimed in .claim 10 wherein said short-step lifting means comprises at least one short-stroke hydraulic jack. 

1. Jacking apparatus of the type which includes a jacking element for raising a load through a plurality of successive substeps and comprising: a. support means, b. a threaded screw, c. means coupling said screw to the load, d. a first nut threadably engaging said screw and at times supported by said support means, e. a second nut also threadably engaging said screw, f. load lifting means for at times moving said second nut together with said screw and the load in the direction of the screw axis, g. nut rotating means for rotating only one of said nuts selectively in either direction about said screw, h. coupling means operatively connected between said first and second nuts and tending to maintain said two nuts in rotatably coincident positions on said screw, i. whereby the action of said lifting means in urging said load away from said support means tends to move said first nut away from said support means and frees said first nut for rotation while simultaneously causing the load to be carried by said screw and through said second nut to said lifting means, anD whereby the relieving of said lifting means causes the load to be carried instead through said first nut to said support means while simultaneously freeing said second nut for rotation, j. and means for restraining rotation of said one nut except in response to said nut rotating means and of the other nut except in response to said coupling means.
 2. Jacking apparatus as claimed in claim 1 wherein said coupling means comprises a resilient means.
 3. Jacking apparatus as claimed in claim 2 wherein said resilient means comprises a spring and means responsive to rotation of said one nut by said nut rotating means for storing energy in said spring.
 4. Jacking apparatus as claimed in claim 3 wherein said spring is a compression spring mounted on either of the two nuts and said coupling means further includes means responsive to rotation of either nut from a predetermined position of rotational coincidence of the two nuts for compressing said spring.
 5. The jacking apparatus of claim 4 which further includes an arcuate slot in said one nut for housing said spring, at least one upstanding pin slidably supported in said slot at an end of said spring, and an aperture in said other nut for securing said pin.
 6. The jacking apparatus of claim 5 in which there are two upstanding pins slidably supported in said slot at opposite ends of said spring, said other nut defining therein two spaced arcuate slots each respectively securing one of said pins, the remote ends of said two spaced slots being spaced circumferentially by a distance corresponding to the circumferential spacing of said two pins when said two nuts are in said rotationally coincident position, the length of each of the spaced arcuate slots being such as to subtend an angle at least equalling the angular rotation imparted to said one nut by said nut rotating means.
 7. A jacking apparatus as claimed in claim 1 wherein said support means restrains the rotation of said first nut when the load is supported by said support means through said first nut.
 8. A jacking apparatus of the type having a support means, a threaded screw, a means coupling the screw to the load, a first nut threadably engaging said screw and at times supported by said support means, a second nut also threadably engaging said screw, and load lifting means for at times moving said second nut together with said screw and the load in the direction of the screw axis, the improvement which comprises: a drive means for rotating only one of said nuts selectively in either direction about said screw, a coupling means which is operatively connected between said first and second nuts and which tends to maintain said nuts in rotatably coincident positions on said screw, and means for restraining the rotation of said one nut except in response to said drive means and the rotation of said other nut means except in response to said coupling means, whereby the action of said lifting means in urging said load away from said support means tends to move said first nut away from said support means and frees said first nut for rotation while simultaneously causing the load to be carried by said screw and through said second nut to said lifting means; and whereby the release of said lifting means causes the load to be carried instead through said first nut to said support means while simultaneously freeing said second nut for rotation.
 9. A jacking apparatus as claimed in claim 8 wherein said coupling means comprises a resilient means.
 10. Jacking apparatus of the type which includes a jacking element for raising the load through a plurality of successive sub-steps and comprising: a. a base having an upwardly extending support means, b. a helically threaded jack post, c. means coupling said jack post to the load, d. a first lower nut threadably engaging said jack post and at times supported by said support means, said support means restraining rotation of said lower nut when supporting said nut, e. a second upper nut Also threadably engaging said jack post, f. short-step load lifting means for at times moving said upper nut together with said jack post and the load in the direction of the post axis, said load lifting means restraining the rotation of said upper nut when said jack post is moved by said lifting means, g. drive means for rotating only one of said nuts selectively in either direction along said jack post, h. coupling means operatively connected between said upper and lower nuts and tending to maintain said nuts in rotatably coincident positions on said screw, i. whereby the action of said lifting means in urging said load away from said support means tends to move said first nut away from said support means and free said lower nut for rotation while simultaneously causing the load to be carried by said screw and through said upper nut to said lifting means, and whereby the relieving of said lifting means causes the load to be carried instead through said lower nut to said support means while simultaneously freeing said second nut for rotation.
 11. A jacking apparatus as claimed in claim 10 which further comprises a lifting plate mounted between said upper and lower nuts with said load lifting means being mounted between said support means and said lifting means.
 12. A jacking apparatus as claimed in claim 10 wherein said short-step lifting means comprises at least one short-stroke hydraulic jack. 